Classifications

• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
  • C08F212/00—Copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by an aromatic carbocyclic ring
  • C08F212/02—Monomers containing only one unsaturated aliphatic radical
  • C08F212/04—Monomers containing only one unsaturated aliphatic radical containing one ring

Definitions

• the invention relates to a method for producing in Water-redispersible vinyl aromatic copolymer redispersible powders as well as the use of the process products.
• Polymer powders redispersible in water which are obtained by drying the corresponding polymer dispersions are accessible, are known and have been used for many years in particular in Construction sector successfully used. They improve the property picture of hydraulically setting systems such as cement mortars, for example, their abrasion resistance, bending tensile strength and liability.
• Hydrate-ethylene copolymers such products are represented on the market, such products based on polyvinyl acetate, Vinyl acetate-ethylene copolymers, vinyl acetate-vinyl ester copolymers and vinyl chloride-ethylene copolymers.
• Suitable vinyl aromatic comonomers a) are styrene and methyl styrene and vinyl toluene, with styrene being preferred.
• Suitable 1,3-diene comonomers (b1) are 1,3-butadiene and isoprene, 1,3-butadiene is preferred.
• Suitable comonomers (b2) from the Examples of the group of alkyl esters of (meth) acrylic acid are Methyl methacrylate, methyl acrylate, n-butyl methacrylate, n-butyl acrylate, Ethyl methacrylate, ethyl acrylate, 2-ethylhexyl methacrylate, 2-ethylhexyl acrylate.
• Methyl methacrylate is preferred, Ethyl acrylate, n-butyl acrylate, 2-ethylhexyl acrylate, especially n-butyl acrylate is preferred.
• Examples of comonomer c) are from the group of carboxylic acids and their anhydrides acrylic acid, methacrylic acid, fumaric acid, Itaconic acid, crotonic acid, maleic acid, mesaconic acid, glutaric acid, Maleic anhydride; from the group of carboxamides Acrylamide, methacrylamide; from the group of sulfonic acids Vinylsulfonic acid, 2-acrylamidopropanesulfonic acid.
• P refer acrylic acid, methacrylic acid, fumaric acid, maleic acid, Maleic anhydride.
• the selection of monomers and the selection of the proportions by weight of the comonomers is carried out such that in general a glass transition temperature Tg of -70 ° C. to + 70 ° C., preferably -50 ° C. to + 50 ° C., in particular 0 ° C. to + 25 ° C results.
• the glass transition temperature Tg of the polymers can be determined in a known manner by means of differential scanning calorimetry (DSC).
• the comonomer mixture contains 20.0 to 79.9% by weight, preferably 30 to 69.9% by weight, vinylaromatic a) and 20 to 79.9% by weight, preferably 30 to 69.9% by weight, 1,3-diene (bl ) or (meth) acrylic acid ester (b2).
• the proportion of comonomer c) is 0.1 to 10% by weight, preferably 2 to 5% by weight, in each case based on the total weight of the comonomer mixture.
• Suitable hydroxycarboxylic acids are organic acids that contain one or more OH groups in the molecule in addition to one or more COOH groups. Monohydroxy and dihydroxy derivatives of mono-, di- or tricarboxylic acids with generally 2 to 10 carbon atoms are preferred. Mandelic acid (hydroxyphenylacetic acid), lactic acid (2-hydroxypropionic acid), malic acid (hydroxysuccinic acid), tartaric acid (2,3-dihydroxybutanedioic acid) and citric acid are particularly preferred.
• citric acid (2-hydroxy-1,2,3-propane tricarboxylic acid) is used.
• the hydroxycarboxylic acids can also be used in the form of one of their salts and here in particular in the form of water-soluble or aqueous-alkaline-soluble salts. These can be, for example, sodium salts, potassium salts, ammonium salts or calcium salts.
• the proportion of hydroxycarboxylic acid is preferably 7 to 30% by weight, based on the proportion of copolymer.
• the emulsifier-stabilized vinylaromatic copolymers are prepared by the emulsion polymerization process, the polymerization temperature generally being 0 ° C. to 100 ° C., preferably 50 ° C.
• the polymerization can be carried out in a batch process, with all components being placed in the reactor, and in a metering process, with one or more components being fed in during the polymerization. Mixed types with feed and dosage are preferred.
• the dosing can be carried out separately (spatially and temporally) or the components to be dosed can be dosed all or in part pre-emulsified.
• emulsifiers As a dispersing agent, all can usually be used in emulsion polymerization used emulsifiers are used, no protective colloids being used as dispersants become. Suitable emulsifiers are both anionic and cationic as well as nonionic emulsifiers. Preferably be the emulsifiers in an amount of 0.1 to 5 wt .-%, based used on the total weight of the monomers.
• anionic surfactants such as alkyl sulfates with a Chain length of 8 to 18 carbon atoms, alkyl or alkylaryl ether sulfates with 8 to 18 carbon atoms in the hydrophobic residue and up to 40 ethylene or propylene oxide units, alkyl or alkylarylsulfonates with 8 to 18 carbon atoms, esters and half esters of sulfosuccinic acid with monohydric alcohols or alkylphenols.
• Suitable nonionic surfactants are, for example, alkyl polyglycol ethers or alkylaryl polyglycol ethers with 8 to 40 ethylene oxide units.
• the initiation takes place by means of the usual, at least partially water-soluble radical generator, which is preferably in Quantities from 0.01 to 3.0% by weight, based on the total weight of the monomers.
• examples include sodium persulfate, Hydrogen peroxide, t-butyl peroxide, t-butyl hydroperoxide, Potassium peroxodisulfate, azobisisobutyronitrile.
• the radical initiators mentioned also in a known manner with 0.01 to 3.0% by weight, based on the total weight of monomers, reducing agents combined become.
• Alkali formaldehyde sulfoxylates are suitable, for example and ascorbic acid.
• With redox initiation preferably one or both redox catalyst components during metered the polymerization.
• n-dodecyl mercaptan t-dodecyl mercaptan
• mercaptopropionic acid mercaptopropionic acid methyl ester
• Isopropanol and acetaldehyde preferably in amounts of 0.1 to 3.0% by weight, based on the total weight of the monomers.
• the aqueous obtained with the inventive method Dispersions have a solids content of 30 to 75% by weight, preferably from 40 to 65% by weight.
• the particle size of the dispersion particles is between 0.05 and 5 ⁇ m, preferably between 0.1 and 0.3 ⁇ m.
• the addition of the hydroxycarboxylic acid component can take place before or during the polymerization or after the completion of the polymerization before drying. Hydroxycarboxylic acid is preferred as an aqueous solution after completion of the polymerization and before added to the drying of the copolymer dispersion.
• the received Mixture preferably has a total solids content before atomization from 25 to 50% by weight, a pH of preferably 6.7 to 7.5, and a Brookfield viscosity (20 rpm) of preferably have 100 to 3000 mPas.
• the aqueous dispersions are dried, for example by means of fluidized bed drying, freeze drying or spray drying.
• the dispersions are preferably spray dried.
• Spray drying takes place in conventional spray drying systems, where the atomization by means of one, two or Multi-component nozzles or with a rotating disc can.
• the exit temperature is generally in the range from 55 ° C to 100 ° C, preferably 70 ° C to 90 ° C, depending on the system, Glass transition temperature of the resin and the desired degree of drying, chosen.
• water-soluble polymers for example from the group of polyvinyl alcohols, starches, Celluloses, casein, melamine formaldehyde sulfonate, naphthalene formaldehyde sulfonates, Poly (meth) acrylic acid as a spraying aid, be added. Drying without addition is preferred of atomization aids.
• the powder composition can be combined with others Additives are modified.
• Additives are modified. examples for this are Antiblocking agents, dyes, pigments, plasticizers, filming aids, Anti-foaming agents, catalysts, rheology aids, Thickeners, adhesives and emulsifiers, if these are liquid in their original state, before the mixing can be converted into a powdery state have to.
• the powder obtained can with an anti-blocking agent (anti-caking agent), preferably up to 30% by weight, based on the total weight of polymer components, be transferred.
• antiblocking agents are kaolin, Ca or Mg carbonate, talc, gypsum, silica, Silicates with particle sizes preferably in the range of 10 nm up to 10 ⁇ m.
• the powdery composition produced according to the invention can by simply stirring (dispersing) in water be completely redispersed at room temperature. Perfectly Redispersed means that by adding sufficient amounts A polymeric redispersion is obtained, its particle size distribution quasi the particle size distribution of the basic dispersion corresponds.
• the hydroxycarboxylic acid-modified water-redispersible Polymer powders can be used in the typical areas of application be used.
• Binders such as cement (Portland, aluminate, trass, Cottage, magnesia, phosphate cement), plaster, water glass, for the Production of building adhesives, plasters, leveling compounds, floor leveling compounds, Concrete repair mortar, grout and paints.
• cement Portableland, aluminate, trass, Cottage, magnesia, phosphate cement
• plaster water glass
• Concrete repair mortar grout and paints.
• a 30% by weight aqueous citric acid solution (2-hydroxy-1,2,3-propane tricarboxylic acid) was added to the dispersion while stirring.
• the corresponding amounts were chosen so that a mixture with a solids content of 15% by weight (18% by weight based on polymer content) of citric acid and 85% by weight of film-forming polymer (resin) was obtained.
• the pH of the citric acid-containing dispersion was then adjusted to pH 7.0 using an aqueous 10% by weight sodium hydroxide solution.
• a stable, coagulate-free mixture was obtained which, at a solids content of 45%, had a viscosity (Brookfield viscometer, 20 ° C., 20 rpm) of 380 mPas.
• the redispersion powder was produced by spray drying in a Nubilosa spray drying system at an inlet temperature of 110 ° C. and an outlet temperature of 80 ° C.
• a kaolin powder with a grain size of approximately 3 ⁇ m was mixed in. The amount was chosen so that 10% by weight of kaolin was present in the powdery composition at the end of drying.
• the dry powder obtained was additionally mixed with 20% by weight of commercially available antiblocking agent (mixture of calcium-magnesium carbonate and magnesium hydrosilicate).
• the powder obtained had an average particle size of 85 ⁇ m . With regard to its properties, the powder proved to be very free-flowing, block-stable (storage-stable), very good and spontaneously redispersible.
• Example 1 The preparation was carried out analogously to Example 1, however the amounts of styrene-butadiene copolymer dispersion and citric acid chosen so that a mixture with a solid portion of 20% by weight (25% by weight based on polymer content) of citric acid and 80% by weight of film-forming polymer (resin) was obtained. All other measures corresponded to example 1.
• the powder obtained had an average particle size of 80 ⁇ m . With regard to its properties, the powder proved to be very free-flowing, block-stable (storage-stable), very good and spontaneously redispersible. By adding water, a polymeric redispersion was obtained with the powder, the particle size distribution of which virtually corresponded to that of the basic dispersion. With regard to the cement stability and influence on the cement setting behavior of the redispersion, no difference to the powder base dispersion was found.
• Example 1 The preparation was carried out analogously to Example 1, but the styrene-butadiene copolymer dispersion was mixed with citric acid and a sodium polyacrylate with a molecular weight of 2000. The corresponding amounts were chosen so that a mixture with a solids content of 10% by weight (12.5% by weight based on polymer content) citric acid, 10% by weight Na polyacrylate and 80% by weight film-forming polymer (resin ) was obtained. All other measures corresponded to Example 1. A stable, coagulate-free mixture was obtained which, at a solids content of 44.8%, had a viscosity (Brookfield viscometer, 20 ° C., 20 rpm) of 335 mPas.
• Brookfield viscometer 20 ° C., 20 rpm
• Example 1 The spray drying of the mixture and the addition of the antiblocking agent were carried out analogously to Example 1.
• the powder obtained had an average particle size of 90 ⁇ m. With regard to its properties, the powder proved to be very free-flowing, block-stable (storage-stable), very good and spontaneously dispersible and redispersible.
• a polymeric redispersion was obtained with the powder, the particle size distribution of which virtually corresponded to that of the basic dispersion. With regard to the cement stability and influence on the cement setting behavior of the redispersion, no difference to the powder base dispersion was found.
• the styrene-butadiene copolymer dispersion used in Examples 1 to 3 was adjusted to pH 7.0 with an aqueous 10% by weight sodium hydroxide solution and then spray-dried without the addition of citric acid or Na polyacrylate. At a solids content of 45%, the dispersion had a viscosity (Brookfield viscometer, 20 ° C., 20 rpm) of 350 mPas.
• the spray drying of the dispersion and the addition of the antiblocking agent were carried out analogously to Example 1.
• the powder obtained had an average particle size of 87 ⁇ m.
• the powder was not redispersible in water. The addition of water did not change the particle size of 87 ⁇ m.
• Example 2 The preparation was carried out analogously to Example 1, but the amounts of styrene-butadiene copolymer dispersion and citric acid were chosen so that a mixture with a solids content of 2% by weight (2.1% by weight based on polymer content), citric acid and 98% by weight .-% film-forming polymer (resin) was obtained. All other measures corresponded to Example 1.
• a stable, coagulate-free mixture was obtained which, at a solids content of 44.5%, had a viscosity (Brookfield viscometer, 20 ° C., 20 rpm) of 330 mPas.
• the spray drying of the mixture and the addition of the antiblocking agent were carried out analogously to Example 1.
• the powder obtained had an average particle size of 85 ⁇ m .
• the powder was not redispersible in water.
• the addition of water did not change the particle size of 85 ⁇ m .

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• Chemical & Material Sciences (AREA)
• Health & Medical Sciences (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Medicinal Chemistry (AREA)
• Polymers & Plastics (AREA)
• Organic Chemistry (AREA)
• Processes Of Treating Macromolecular Substances (AREA)
• Addition Polymer Or Copolymer, Post-Treatments, Or Chemical Modifications (AREA)
• Compositions Of Macromolecular Compounds (AREA)
• Polymerisation Methods In General (AREA)
• Paints Or Removers (AREA)
• Adhesives Or Adhesive Processes (AREA)

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• 1999
  • 1999-06-24 DE DE19929008A patent/DE19929008A1/de not_active Withdrawn
• 2000
  • 2000-06-02 DE DE50000010T patent/DE50000010D1/de not_active Expired - Fee Related
  • 2000-06-02 AT AT00111073T patent/ATE204307T1/de not_active IP Right Cessation
  • 2000-06-02 EP EP00111073A patent/EP1065226B1/de not_active Expired - Lifetime
  • 2000-06-02 ES ES00111073T patent/ES2162779T3/es not_active Expired - Lifetime
  • 2000-06-12 US US09/592,997 patent/US6348532B1/en not_active Expired - Fee Related
  • 2000-06-21 JP JP2000186485A patent/JP3226912B2/ja not_active Expired - Fee Related
  • 2000-06-21 PL PL00340949A patent/PL340949A1/xx not_active Application Discontinuation

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